T&T: Autopilots on Auto..Auto..Auto - Different Ships, Different Long Splices

[Milt Baker]

Mike,

To me, good bridge management is more art than science.  I would argue that on long offshore passages one can have an electronic charting program or GPS receiver steer the boat with an autopilot and still be a competent captain who is not hazarding his ship or crew.  I usually choose to allow my GPS or Nobeltec computer to steer our boat on long offshore passages and in tens of thousands of miles have yet to experience a problem in doing so.  A recent example: I relied on Nobeltec and my Windows-based laptop for steering over more than 8,500 NM between Sept. 2005 and Oct. 2006 and never once had an off-course problem.  I am the first to admit, however, that may be because we have some built-in safeguards:

	--If our autopilot stops receiving an input from the selected NAV device (either GPS or Nobeltec computer), the autopilot sounds a sing-song alarm to alert the crew that there is no NAV input and the person on watch springs into action, taking control until the problem is sorted out.  (In practice, this is a rare occurrence.)

	--Every few minutes the person on watch physically verifies the course being steered (as shown on the main ship's compass) against the GPS/Nobeltec course to the waypoint. This is a matter of crew training, but it works.  

	--On offshore passages, we log the ship's position, magnetic course (taken from the main compass), speed and other data in a handwritten log every hour on the hour (after the reminder alarm goes off!).  If the person on watch has been inattentive and we have had some kind of malfunction causing the autopilot to steer the wrong course, it should be immediately apparent to the person on watch at the time the log entries are made and compared to those made the previous hour.  

	--While electronic charting programs or the computers that run them can indeed hang from time to time, we reduce the odds by using the navigation computer ONLY for navigation--not for e-mail, weather, Internet, movies, music, games, word processing, spreadsheets, or other tasks.  Moreover, we reboot it at least once every 24 hours and, as a matter of course, we also reboot about an hour before our ETA at the sea buoy.  This seems to keep our computer problems and hangs to a minimum. (We also carry three backup laptop nav computers, each with the charting program installed and the serial ports pre-configured, so changing one for another is a three-minute exercise.  In the last year, we've had to do this exactly once--and time was not of the essence on that single occasion; we were in port in Venezuela.) 

	--On an offshore passage, whenever we are approaching a critical waypoint, aid to navigation or navigation danger, the captain is in the wheelhouse.  He is not necessarily conning the vessel, but he’s there to make sure that the "feel" of the situation is right.

	--No matter how good a helmsman the person on watch is, the autopilot can steer a better course—something we especially appreciate in thick fog or heavy rain where outside visual cues are limited.  You’re right: getting practice hand-steering the boat is a GOOD thing for everyone who stands a watch, a basic step in watchstander qualification.  But it's not the only thing.  We let the autopilot steer simply because it's our best helmsman.

In practice, I find that using Nobeltec or a GPS receiver to keep our cross track error down to just about zero works well for me on offshore passages.  While a Windows-based computer has a mean time between failures (MTBF) far greater than that of a fluxgate compass, I'd guess the MTBF of my Furuno GPS receivers (including signal loss so severe that LAT/LON, COG and SOG are lost) is no greater at all.  Not, at least, in my experience.  That's why we always have our key waypoints plugged into both our Nobeltec computer and two of our Furuno GPS receivers.  Belt and suspenders!  Changing from one to another is easily accomplished by anyone who stands a watch aboard Bluewater.

I spent twenty years in the U.S. Navy, an outfit called by a character in Herman Wouk's Caine Mutiny, "an organization designed by geniuses to be run by idiots."  As one of the "idiots," standing many hours of bridge watch I absorbed a fair amount about bridge management, redundancy, and keeping one's eye on the ball.  So much so, in fact, it's instinctive to me today.  And I try to pass it on to those who stand watch aboard my boat.

It's not the electronics that make the mistakes; it's the people operating them!  (The Nordhavn 62 grounding in Mexico you cite is probably a good example.)  The real key is for any watch officer to stay alert and challenge, challenge, challenge the information he's getting--and to make sure it is in synch with all the other information.  A good watchstander uses all the information available, including his senses, and before long just "knows" when something is wrong.  Pilots call it situational awareness.

I am not saying that my way is better than yours, but it works for me.   With the fantastic tools we now have available, navigation today offers many personal choices, and being dogmatic about a single best way to do it doesn't work for me.  There's a way we do it aboard my boat, but when I am aboard your boat I'll do it your way--and with a smile.  

Different ships, different long splices!

--Milt Baker, Nordhavn 4732 Bluewater